Trimethyl orthoformate → ethyl 4-methyl-2-(5-oxo-1H-1,2,4-triazol-4(5H)-yl)thiazole-5-carboxylate

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Reaction Steps

A solution of ethyl 2-(hydrazinecarboxamido)-4-methylthiazole-5-carboxylate (0.50 g, 2.05 mmol), trimethyl orthoformate (0.25 mL, 2.28 mmol) and p-toluenesulfonic acid monohydrate (10 mg) in methanol (10 mL) was subjected to microwave irradiation for 10 minutes at 90° C. (30 psi). The solvent was removed in vacuo and the residue was suspended in dichloromethane. The solid was collected by filtration, washed with saturated sodium bicarbonate and water, and dried to afford the title compound in 73% yield (0.38 g): 1H NMR (300 MHz, DMSO-d6) δ 8.33 (s, 1H), 4.32 (q J=6.9 Hz, 2H), 2.68 (s, 3H), 1.35 (t, J=6.9 Hz, 3H); MS (ES+) m/z 255.2 (M+1).

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